Field of the Invention
The present invention relates to a display apparatus and a control method thereof.
Description of the Related Art
As a technique related to a liquid crystal display apparatus, a technique to control emission brightness (light emission amount) of a backlight based on input image data is available. If this technique is used, contrast of a display image (image displayed on the screen) can be increased, and power consumption of the display apparatus can be reduced. If the emission brightness of a plurality of light sources constituting the backlight is individually controlled, or if input image data is corrected according to the emission brightness of the backlight, then contrast of the display image can be further improved.
Furthermore, if three light-emitting devices, that is, an R device that emits red light, a G device that emits green light and a B device that emits blue light, are used as the light source of the backlight, the emission color of the light source can be controlled by individually controlling the emission brightness (light emission amount) of the three light-emitting devices. Then the color gamut of the display image can be expanded by controlling the emission color of the light source based on the input image data.
The technique to control the emission color of the light source is disclosed, for example, in Japanese Patent Application Laid-open No. 2009-53687 and in Japanese Patent Application Laid-open No. 2007-322944.
Using the technique disclosed in Japanese Patent Application Laid-open No. 2009-53687, one of the three emission colors of the three light-emitting devices is detected as a dominant color component of the input image data. Then the emission brightness of the light-emitting device having the detected emission color is maximized (emission brightness of the light-emitting devices having emission color other than the detected emission color is decreased), whereby the color parity of the dominant color component of the input image data is enhanced.
In the case of the technique disclosed in Japanese Patent Application Laid-open No. 2007-322944, the emission color of the light source is controlled such that the color with chromaticity that is close to the chromaticity of the input image data is emitted from the light source, whereby the color gamut of the display image is expanded.